Web mining is a new developing research discipline and also it is subdivision of Data Mining , it has attracted a great deal of attention in the Information Technology and in society as a whole in recent years, due to the wide range and availability of huge amount of heterogeneous data. The web has become versatile tool for almost all application today. Mine this available huge data to make it proper use and presentable, giving right solution to a particular problem is a big real challenge . In this paper deals with a introductory idea about the data mining, web mining , web log mining and challenges of mining the web data.